Chaining and trimming device

ABSTRACT

Apparatus for trimming and chaining threads during the chain stitching of articles. The apparatus includes a feed wheel which interacts with a hard surface to trim the chain thread and with a second wheel to provide chaining. Pneumatic means position the feed wheel for trimming and chaining operations.

United States Patent i [72] Inventors Francis H. Hughes;

Douglas J. Crawford, both of Troy, N.Y. [2]] Appl. No. 12,410 [22] Filed Feb. 18, 1970 [45] Patented July 6, 1971 [73] Assignee Cluett, Peabody & Co., Inc.

Troy, N.Y.

[S4] CHAINING AND TRIMMING DEVICE 12 Claims, 8 Drawing Figs. 52] uscl 112/252, 1 12/214 [51] Int. Cl D05b 65/04 [50] Field oiSearch 112/252, 130,129,212, 214

[56] References Cited UNITED STATES PATENTS 2,293,096 8/1942 Anderson 1 12/252 2,423,080 7/1947 Belcher et a1. 1 12/130 X 2,705,466 6/1955 Sargrove et a1. 112/252 2,730,977 1/1956 Hayes et a1. 112/214 3,008,437 11/1961 Herr 112/121.15 X 3,188,992 6/1965 Freeman et al. 112/252 3,329,113 7/1967 Lewis etal......... 112/130 3,425,377 2/1969 Scharmer,.1r. 1 12/214 X Primary Examiner-James R. Boler Attorneys-Leo Fomero, RobertJ. Dockery and Robert .1.

Seligman ABSTRACT: Apparatus for trimming and chaining threads during the chain stitching of articles. The apparatus includes a feed wheel which interacts with a hard surface to trim the chain thread and with a second wheel to provide chaining. Pneumatic means position the feed wheel for trimming and chaining operations.

PATENIEUJUL SIQTI 34590758 sum 1 [IF 2 FRANCIS H. HUGHES DOUGLAS J. CRAWFORD [NVENTURS BY M afifimk a WATTORNEY PATENTEDJUL SIB?! 3,590,758

SHEET 2 [IF 2 C C 54 4a 72 45 v B 26 36 47 46 FIG. 6

TWA P-A T 2 g 7:! D|A SIA '1: g i D D TD-a FRANCIS H. HUGHES DOUGLAS J". CRAWFORD INVEN'I'ORS liY ATToRNEV CHAINING AND TRIMMING DEVICE BACKGROU ND OF THE INVENTION The field of the present invention is accessories and attachments for sewing machines and the like and more particularly a trimming and chaining apparatus for severing chain seamed articles passing through the machine without disturbing the continuous chain for the next workpiece.

A variety of devices have been used in the past to trim the leading and trailing ends of chain stitched articles. One such device is described in the U.S. Pat. No. 3,008,437 to John Herr, issued Nov. I4, 1961. In a thread chain cutter of the type shown in the Herr patent, a wire is heated to incandescence to sever the thread chain by burning. One ofthe disadvantages inherent in this type of apparatus is the numerous heating and insulating considerations which are encountered. Another disadvantage is that a minimum length of chain thread must remain untouched in order to avoid searing the garment material.

Another device (U.S. Pat. No. 2,334,672) used to sever chain thread utilizes a cutting notch positioned near the stitching point. When the garment is removed from the sewing machine, the chain thread is drawn across the notch. When the cutting edges of the notch become dull, however, an increased tension must be exerted on the chain thread when drawing it across the notch in order to sever the same. Drawing the thread in this manner might cause the stitched garment to become puckered.

Under other operating practices, the chain thread is manually severed. Such practice, however, is expensive and time consuming.

SUMMARY OF THE INVENTION The present invention overcomes the foregoing and other disadvantages and accordingly, it is an object of this invention to provide an automatic cutting and chaining arrangement that is rugged and economical.

It is another object of the present invention to provide a chain thread cutter which will sever the chain thread sufficiently close to the material to obviate further trimming.

Still another object of this invention is to provide an automatic attachment which is operable to cut the chain threads at the end of each workpiece without disturbing the continuous chain for the next workpiece.

In accordance with one embodiment of the present invention, the chain thread is chained by two mating rollers and is severed by the interaction between one of the rollers and a trimming plate. The trimming plate includes a vacuum hole for drawing away the severed threads.

To accomplish the foregoing and other objects, the present invention comprises the features hereinafter described and particularly set out in the claims, the description setting forth in detail certain illustrative embodiments of the invention.

THE DRAWINGS For a more complete understanding of the invention, reference should be made to the drawings, wherein:

FIG. 1 is an overall perspective view of a machine constructed according to the present invention.

FIG. 2 is a detail view ofa part of the device shown in FIG. 1.

FIG. 3 is a fragmentary vertical sectional view taken on the line A-A in FIG. I.

FIG. 4 is a detail plan view ofa portion of the device of FIG. 2.

FIG. Sis a side elevation taken along the line 8-8 in FIG. 3.

FIG. 6 is a plan view of an alternate embodiment of the device of FIG. 2.

FIG. 7 is a side elevation taken along the line C-C in FIG. 6.

FIG. 8 is a schematic circuit diagram for the device illustrated in FIG. 2.

THE INVENTION Referring to the drawings and specifically to FIGS. 1 and 2, the embodiment of the invention illustrated therein includes a supporting table 10 upon which is mounted a sewing machine 12 and conveying mechanism 14 which may include a folder for moving the work to the sewing machine. The sewing machine is typically of the chain stitch seam type and comprises a bed 16 including a bed plate 17, a standard 18, a bracket arm 19 overhanging the bed 16 and terminating in a sewing head 20. The machine has been modified by removal of the feed dog and feeding is accomplished by two pairs of belts 22 and 23 which capture the garment part and carry it past the sewing head. Each belt pair typically includes an upper and lower belt. Alternatively a single top belt or a pair of top belts could be used. In the latter instance, the work would be captured between the belt or belts and the table top rather than between upper and lower belts. Rolls 11, Ila, 13, 13a, 31 and 32 are typically idler rolls. Rollers 31 and 32 may be driven and are rotatably mounted on shaft 33 which can be positioned so as to exert a downward force on the belt pairs, sandwiching the garment part therebetween. A chaining and trimming device 25 is located in close proximity to the point of stitch formation and maintains chaining between garment parts in addition to trimming the chain at the leading and trailing ends of the garments.

The sewing machine is driven by a belt 63 from clutch motor 64. The motor is engaged by an air piston 65 mounted to the motor operating lever 66. The clutch is engaged and the head is driven only while a garment is passing through the sewing station. The detection and control of this function can be accomplished by any of numerous devices common in the art. In the present embodiment, a retroreflective photohead 50 is mounted on sewing head 20 and directs a beam of light onto retroreflective tape 52 mounted in the sewing bed 16. When a garment part covers tape 52, associated control relays are activated so as to initiate the desired machine action.

At the point where a needle 30 penetrates bed plate 17, which is the point of stitch formation, there is provided a throat plate 26 having a needle aperture 27. The pressure mechanism of the sewing machine comprises a presser foot 28 mounted on the lower end of presser bar 29 that is in turn operatively attached to the sewing head 20. The presser foot simply acts as a stripper when the needle is in the upward stroke. The stitching mechanism of the sewing machine is typically of the single needle variety.

Referring to FIGS. 2, 3 and 4, throat plate 26 includes grooves 36 and 37 which guide belt pairs 22 and 23 (FIG. 1) past the sewing machine needle. (It may be desirable in some applications to use only a single pair of belts). A block 38 (FIG. 3) is fixedly attached to the underside of throat plate 26, and rotatably supports an elastomeric roller 40 which may be a rubber roller, which roller extends into opening 41 of the throat plate. Trimming block 42 is adjustably mounted on the throat plate and may include a vacuum hole 43 for drawing away trimmed threads and a sloped portion 44 over which the thread passes. A feed wheel 45 is journaled on shaft 46 which shaft is rotatably supported by bearing block 47. A plurality of teeth 49 may surround the periphery of the feed wheel. Alternatively the surface may be knurled. Trimming block 42 can be positioned in the direction of thread movement to maintain proper contact pressure between feed wheel 45 and sloped portion 44.

Since there is no feed dog, continuous chaining between garment parts is accomplished by the rotary motion of the feed wheel against the rubber roller. The feed roller 45 is held against rubber roller 40 by the compressive force exerted by a coiled spring 48 on hearing block 47 (FIG. 5). Suitable adjustments (not shown) are provided to position the bearing block and to thereby locate the feed wheel with respect to the rubber roller and the sloped portion of the trimming block.

Mounted on the sewing machine bracket 19 is a double acting pneumatic cylinder 54 (FIG. 1). The cylinder rod 56 is fixedly attached to shaft 46 of the feed wheel and can move the latter between any of three operating positions viz. up, chain or trim. When trimming of the chain thread is desired, rod 56 exerts a downward force on the feed wheel. This downward movement of the feed wheel compresses the rubber roller and simultaneously forces the toothed feed wheel against sloped portion 44 thereby fracturing the chain thread. During stitching, rod 56 raises the feed roller to its up position so that feed roller 45 contacts neither the rubber roller nor the sloped portion.

Referring to FIG. 5, the drive shaft 46 of feed roller 45 is coupled by universal joint 72 to a variable speed drive unit 60 which receives its input from the sewing head drive belt pulley 63 (FIG. 1). Thus feed roller 45 is operated simultaneously with the sewing head.

FIG. 6 shows another embodiment of the instant invention wherein a leaf spring 70 is welded onto the throat plate in place ofa rubber roller. Thread guides 74 and 75 are provided near the free end of spring 70. In this embodiment, chaining is accomplished by the interaction of the feed wheel with the spring. Trimming is achieved by moving the feed wheel into contact with sloped portion 44 so as to fracture the thread. Leaf spring 70 yields to the downward motion of the feed wheel during trimming.

HO. 8 is an across the line wiring diagram in which time delay relays are indicated by the letters TD with an appropriate subscript and the relay contacts are indicated by the letters TD-A, TD-B, etc. The relay contacts are indicated by parallel lines if normally open; the parallel lines are traversed by a diagonal line if normally closed. ln FIG. 8 the contacts are shown with relays TD energized and TD deenergized. Photoelectric relay P, operatively associated with retroreflective tape 52 (FIG. 1), is deenergized. The coils of the solenoids which operate the air cylinder valves are indicated by the letter V with appropriate subscripts. D,, D and D are diodes which convert alternating current into pulsating halfwave current. D and D are blocking diodes; 'R, and R are current limiting resistors. Switch S is normally open and is used to manually energize coil V,. S is interconnected with S and is normally closed, connecting indicator lamp L across the line. Switches S and S are normally closed.

With particular reference to FIGS. 2 and 8, a typical operating sequence will be considered where the apparatus is in a position which exists just prior to seaming. In this position, retrorefleetive tape 52 is uncovered and therefore photoelectric relay P is deenergized. Current flowing through contact P-A will charge capacitor C Similarly, relay TD is energized through contact P-C. Feed roller 45 is in the chaining position and contacts rubber roller 40 through the action of spring 48. When a garment covers retroreflective tape 52, relay P is energized. P opens and P,, closes permitting capacitor C to discharge through solenoid coil V Solenoid coil V is operatively associated with pneumatic cylinder 54 (FIG. I) and causes the same to move feed roller 38 vertically downward so as to trim the leading edge of the garment thread chain. Contact P-D has also closed energizing relay TD,. After a delay, contact TD -B closes and carries current to solenoid coil V Capacitor C is charged. Energizing V actuates cylinder 54 bringing feed roller 45 to its up position. With contact P-C open, relay TD is deenergized. Contact TD -A closes and TD,-B opens. Capacitor C is thus charged.

When stitching is complete, the garment uncovers retroreflective tape 52, deenergizing relay P. Contact P-D opens, deenergizing relay TD As a result, solenoid coil V is deenergized; feed roller 45 is returned to its chain position by spring 48. Relay TD, has been energized, closing contact TD,-B. Capacitor C discharges into solenoid coil V as a result of which the feed roller trims the trailing edge of the garment thread chain. The feed roller then returns to its neutral position.

Although the present invention has been described with reference to specific apparatus, it will be appreciated by a person skilled in the art that a wide variety of changes may be made without departing from the scope of this invention. For example, the apparatus could be inverted while maintaining the relative positions between the feed wheel, rubber wheel and sloped surface. Additionally, certain features of the apparatus may be used independently of others and equivalents may be substituted for the various apparatus elements, all within the spirit and scope of the invention.

We claim:

1. A trimming and chaining apparatus for a sewing machine comprising a wheel adapted to be driven during sewing and having a periphery at least the width of the thread stitch; a yieldable member located such that the thread stitch passes between said member and said wheel; a hard member located adjacent to the yieldable member, both of said members located such that the thread stitch passes between said members and said wheel; and means for moving the wheel first against said yieldable member for chaining and then against said hard member for trimming the thread.

2. The apparatus of claim 1 wherein the periphery of said wheel is a knurled surface.

3. The apparatus of claim 1 wherein the periphery of said wheel is a tooth surface.

4. The apparatus of claim 1 including a vacuum port located adjacent to the hard member and in the path of the thread stitch.

5. The apparatus of claim 1 including a coiled spring for urging said wheel against said yieldable member.

6. The apparatus of claim 5 including an air cylinder for forcing said wheel against said hard member.

7. The apparatus of claim 11 wherein the yieldable member is a rotatable wheel having an elastomeric surface.

8. The apparatus of claim 1 wherein the yieldable member is a leaf spring.

9. Apparatus of claim 7 including a first pair of endless belts located so as to pass generally beneath the sewing head so as to advance the workpiece and a throat plate having an opening wherein said elastomeric surfaced wheel is disposed and said hard member comprises a beveled surface ahead of the opening with respect to the advance of the workpiece.

10. The apparatus of claim 9 wherein the throat plate includes a first slot for guiding said first pair of endless belts.

11. The apparatus of claim 9 including a second pair of endless belts adapted to run parallel with said first endless belt pair and spaced apart from said first endless belt pair such that said opening and said beveled surface lie between said first and said second endless belt pairs.

12. The apparatus of claim 11 including a second slot for guiding said second endless belt pair. 

1. A trimming and chaining apparatus for a sewing machine comprising a wheel adapted to be driven during sewing and having a periphery at least the width of the thread stitch; a yieldable member located such that the thread stitch passes between said member and said wheel; a hard member located adjacent to the yieldable member, both of said members located such that the thread stitch passes between said members and said wheel; and means for moving the wheel first against said yieldable member for chaining and then against said hard member for trimming the thread.
 2. The apparatus of claim 1 wherein the periphery of said wheel is a knurled surface.
 3. The apparatus of claim 1 wherein the periphery of said wheel is a tooth surface.
 4. The apparatus of claim 1 including a vacuum port located adjacent to the hard member and in the path of the thread stitch.
 5. The apparatus of claim 1 including a coiled spring for urging said wheel against said yieldable member.
 6. The apparatus of claim 5 including an air cylinder for forcing said wheel against said hard member.
 7. The apparatus of claim 1 wherein the yieldable member is a rotatable wheel having an elastomeric surface.
 8. The apparatus of claim 1 wherein the yieldable member is a leaf spring.
 9. Apparatus of claim 7 including a first pair of endless belts located so as to pass generally beneath the sewing head so as to advance the workpiece and a throat plate having an opening wherein said elastomeric surfaced wheel is disposed and said hard member comprises a beveled surface ahead of the opening with respect to the advance of the workpiece.
 10. The apparatus of claim 9 wherein the throat plate includes a first slot for guiding said first pair of endless belts.
 11. The apparatus of claim 9 including a second pair of endless belts adapted to run parallel with said first endless belt pair and spaced apart from said first endless belt pair such that said opening and said beveled surface lie between said first and said second endless belt pairs.
 12. The apparatus of claim 11 including a second slot for guiding said seconD endless belt pair. 